A 43-year-old rail construction worker has died from head injuries he sustained in a 10 metre-deep tunnel in London.
Emergency services were called to the Crossrail construction site at Fisher Street in Holborn where they found the man in cardiac arrest. The man has not been named.
A London Ambulance Service spokeswoman said two ambulances, an emergency car and a hazardous area response team rushed to the scene at 5.21am.
She added that despite paramedics' and doctors' "extensive efforts" the man was pronounced dead at the scene.
Police said the Health and Safety Executive (HSE) had been informed.
The £15bn line will run from Maidenhead and Heathrow airport in the west, to Abbey Wood and Shenfield in the east via central London. It is due to start operations in 2018.
A Crossrail spokesman said: "Our first and foremost thoughts are with the family and friends affected by this. The next of kin are being informed.
"We are establishing the facts and a full investigation into the incident has commenced."